The Tor Browser: services/sync/modules/policies.js@b8a032363ba2 (annotated)

services/sync/modules/policies.js@b8a032363ba2 (annotated)

services/sync/modules/policies.js

Thu, 22 Jan 2015 13:21:57 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 22 Jan 2015 13:21:57 +0100
branch: TOR_BUG_9701
changeset 15: b8a032363ba2
permissions: -rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 this.EXPORTED_SYMBOLS = [
   "ErrorHandler",
   "SyncScheduler",
 ];
 const {classes: Cc, interfaces: Ci, utils: Cu, results: Cr} = Components;
 Cu.import("resource://gre/modules/Log.jsm");
 Cu.import("resource://services-sync/constants.js");
 Cu.import("resource://services-sync/engines.js");
 Cu.import("resource://services-sync/util.js");
 Cu.import("resource://gre/modules/FileUtils.jsm");
 Cu.import("resource://gre/modules/NetUtil.jsm");
 XPCOMUtils.defineLazyModuleGetter(this, "Status",
                                   "resource://services-sync/status.js");
 this.SyncScheduler = function SyncScheduler(service) {
   this.service = service;
   this.init();
 }
 SyncScheduler.prototype = {
   _log: Log.repository.getLogger("Sync.SyncScheduler"),
   _fatalLoginStatus: [LOGIN_FAILED_NO_USERNAME,
                       LOGIN_FAILED_NO_PASSWORD,
                       LOGIN_FAILED_NO_PASSPHRASE,
                       LOGIN_FAILED_INVALID_PASSPHRASE,
                       LOGIN_FAILED_LOGIN_REJECTED],
   /**
    * The nsITimer object that schedules the next sync. See scheduleNextSync().
    */
   syncTimer: null,
   setDefaults: function setDefaults() {
     this._log.trace("Setting SyncScheduler policy values to defaults.");
     let service = Cc["@mozilla.org/weave/service;1"]
                     .getService(Ci.nsISupports)
                     .wrappedJSObject;
     let part = service.fxAccountsEnabled ? "fxa" : "sync11";
     let prefSDInterval = "scheduler." + part + ".singleDeviceInterval";
     this.singleDeviceInterval = Svc.Prefs.get(prefSDInterval) * 1000;
     this.idleInterval         = Svc.Prefs.get("scheduler.idleInterval")         * 1000;
     this.activeInterval       = Svc.Prefs.get("scheduler.activeInterval")       * 1000;
     this.immediateInterval    = Svc.Prefs.get("scheduler.immediateInterval")    * 1000;
     this.eolInterval          = Svc.Prefs.get("scheduler.eolInterval")          * 1000;
     // A user is non-idle on startup by default.
     this.idle = false;
     this.hasIncomingItems = false;
     this.clearSyncTriggers();
   },
   // nextSync is in milliseconds, but prefs can't hold that much
   get nextSync() Svc.Prefs.get("nextSync", 0) * 1000,
   set nextSync(value) Svc.Prefs.set("nextSync", Math.floor(value / 1000)),
   get syncInterval() Svc.Prefs.get("syncInterval", this.singleDeviceInterval),
   set syncInterval(value) Svc.Prefs.set("syncInterval", value),
   get syncThreshold() Svc.Prefs.get("syncThreshold", SINGLE_USER_THRESHOLD),
   set syncThreshold(value) Svc.Prefs.set("syncThreshold", value),
   get globalScore() Svc.Prefs.get("globalScore", 0),
   set globalScore(value) Svc.Prefs.set("globalScore", value),
   get numClients() Svc.Prefs.get("numClients", 0),
   set numClients(value) Svc.Prefs.set("numClients", value),
   init: function init() {
     this._log.level = Log.Level[Svc.Prefs.get("log.logger.service.main")];
     this.setDefaults();
     Svc.Obs.add("weave:engine:score:updated", this);
     Svc.Obs.add("network:offline-status-changed", this);
     Svc.Obs.add("weave:service:sync:start", this);
     Svc.Obs.add("weave:service:sync:finish", this);
     Svc.Obs.add("weave:engine:sync:finish", this);
     Svc.Obs.add("weave:engine:sync:error", this);
     Svc.Obs.add("weave:service:login:error", this);
     Svc.Obs.add("weave:service:logout:finish", this);
     Svc.Obs.add("weave:service:sync:error", this);
     Svc.Obs.add("weave:service:backoff:interval", this);
     Svc.Obs.add("weave:service:ready", this);
     Svc.Obs.add("weave:engine:sync:applied", this);
     Svc.Obs.add("weave:service:setup-complete", this);
     Svc.Obs.add("weave:service:start-over", this);
     Svc.Obs.add("FxA:hawk:backoff:interval", this);
     if (Status.checkSetup() == STATUS_OK) {
       Svc.Idle.addIdleObserver(this, Svc.Prefs.get("scheduler.idleTime"));
     }
   },
   observe: function observe(subject, topic, data) {
     this._log.trace("Handling " + topic);
     switch(topic) {
       case "weave:engine:score:updated":
         if (Status.login == LOGIN_SUCCEEDED) {
           Utils.namedTimer(this.calculateScore, SCORE_UPDATE_DELAY, this,
                            "_scoreTimer");
         }
         break;
       case "network:offline-status-changed":
         // Whether online or offline, we'll reschedule syncs
         this._log.trace("Network offline status change: " + data);
         this.checkSyncStatus();
         break;
       case "weave:service:sync:start":
         // Clear out any potentially pending syncs now that we're syncing
         this.clearSyncTriggers();
         // reset backoff info, if the server tells us to continue backing off,
         // we'll handle that later
         Status.resetBackoff();
         this.globalScore = 0;
         break;
       case "weave:service:sync:finish":
         this.nextSync = 0;
         this.adjustSyncInterval();
         if (Status.service == SYNC_FAILED_PARTIAL && this.requiresBackoff) {
           this.requiresBackoff = false;
           this.handleSyncError();
           return;
         }
         let sync_interval;
         this._syncErrors = 0;
         if (Status.sync == NO_SYNC_NODE_FOUND) {
           this._log.trace("Scheduling a sync at interval NO_SYNC_NODE_FOUND.");
           sync_interval = NO_SYNC_NODE_INTERVAL;
         }
         this.scheduleNextSync(sync_interval);
         break;
       case "weave:engine:sync:finish":
         if (data == "clients") {
           // Update the client mode because it might change what we sync.
           this.updateClientMode();
         }
         break;
       case "weave:engine:sync:error":
         // `subject` is the exception thrown by an engine's sync() method.
         let exception = subject;
         if (exception.status >= 500 && exception.status <= 504) {
           this.requiresBackoff = true;
         }
         break;
       case "weave:service:login:error":
         this.clearSyncTriggers();
         if (Status.login == MASTER_PASSWORD_LOCKED) {
           // Try again later, just as if we threw an error... only without the
           // error count.
           this._log.debug("Couldn't log in: master password is locked.");
           this._log.trace("Scheduling a sync at MASTER_PASSWORD_LOCKED_RETRY_INTERVAL");
           this.scheduleAtInterval(MASTER_PASSWORD_LOCKED_RETRY_INTERVAL);
         } else if (this._fatalLoginStatus.indexOf(Status.login) == -1) {
           // Not a fatal login error, just an intermittent network or server
           // issue. Keep on syncin'.
           this.checkSyncStatus();
         }
         break;
       case "weave:service:logout:finish":
         // Start or cancel the sync timer depending on if
         // logged in or logged out
         this.checkSyncStatus();
         break;
       case "weave:service:sync:error":
         // There may be multiple clients but if the sync fails, client mode
         // should still be updated so that the next sync has a correct interval.
         this.updateClientMode();
         this.adjustSyncInterval();
         this.nextSync = 0;
         this.handleSyncError();
         break;
       case "FxA:hawk:backoff:interval":
       case "weave:service:backoff:interval":
         let requested_interval = subject * 1000;
         this._log.debug("Got backoff notification: " + requested_interval + "ms");
         // Leave up to 25% more time for the back off.
         let interval = requested_interval * (1 + Math.random() * 0.25);
         Status.backoffInterval = interval;
         Status.minimumNextSync = Date.now() + requested_interval;
         this._log.debug("Fuzzed minimum next sync: " + Status.minimumNextSync);
         break;
       case "weave:service:ready":
         // Applications can specify this preference if they want autoconnect
         // to happen after a fixed delay.
         let delay = Svc.Prefs.get("autoconnectDelay");
         if (delay) {
           this.delayedAutoConnect(delay);
         }
         break;
       case "weave:engine:sync:applied":
         let numItems = subject.succeeded;
         this._log.trace("Engine " + data + " successfully applied " + numItems +
                         " items.");
         if (numItems) {
           this.hasIncomingItems = true;
         }
         break;
       case "weave:service:setup-complete":
          Services.prefs.savePrefFile(null);
          Svc.Idle.addIdleObserver(this, Svc.Prefs.get("scheduler.idleTime"));
          break;
       case "weave:service:start-over":
          this.setDefaults();
          try {
            Svc.Idle.removeIdleObserver(this, Svc.Prefs.get("scheduler.idleTime"));
          } catch (ex if (ex.result == Cr.NS_ERROR_FAILURE)) {
            // In all likelihood we didn't have an idle observer registered yet.
            // It's all good.
          }
          break;
       case "idle":
         this._log.trace("We're idle.");
         this.idle = true;
         // Adjust the interval for future syncs. This won't actually have any
         // effect until the next pending sync (which will happen soon since we
         // were just active.)
         this.adjustSyncInterval();
         break;
       case "active":
         this._log.trace("Received notification that we're back from idle.");
         this.idle = false;
         Utils.namedTimer(function onBack() {
           if (this.idle) {
             this._log.trace("... and we're idle again. " +
                             "Ignoring spurious back notification.");
             return;
           }
           this._log.trace("Genuine return from idle. Syncing.");
           // Trigger a sync if we have multiple clients.
           if (this.numClients > 1) {
             this.scheduleNextSync(0);
           }
         }, IDLE_OBSERVER_BACK_DELAY, this, "idleDebouncerTimer");
         break;
     }
   },
   adjustSyncInterval: function adjustSyncInterval() {
     if (Status.eol) {
       this._log.debug("Server status is EOL; using eolInterval.");
       this.syncInterval = this.eolInterval;
       return;
     }
     if (this.numClients <= 1) {
       this._log.trace("Adjusting syncInterval to singleDeviceInterval.");
       this.syncInterval = this.singleDeviceInterval;
       return;
     }
     // Only MULTI_DEVICE clients will enter this if statement
     // since SINGLE_USER clients will be handled above.
     if (this.idle) {
       this._log.trace("Adjusting syncInterval to idleInterval.");
       this.syncInterval = this.idleInterval;
       return;
     }
     if (this.hasIncomingItems) {
       this._log.trace("Adjusting syncInterval to immediateInterval.");
       this.hasIncomingItems = false;
       this.syncInterval = this.immediateInterval;
     } else {
       this._log.trace("Adjusting syncInterval to activeInterval.");
       this.syncInterval = this.activeInterval;
     }
   },
   calculateScore: function calculateScore() {
     let engines = [this.service.clientsEngine].concat(this.service.engineManager.getEnabled());
     for (let i = 0;i < engines.length;i++) {
       this._log.trace(engines[i].name + ": score: " + engines[i].score);
       this.globalScore += engines[i].score;
       engines[i]._tracker.resetScore();
     }
     this._log.trace("Global score updated: " + this.globalScore);
     this.checkSyncStatus();
   },
   /**
    * Process the locally stored clients list to figure out what mode to be in
    */
   updateClientMode: function updateClientMode() {
     // Nothing to do if it's the same amount
     let numClients = this.service.clientsEngine.stats.numClients;
     if (this.numClients == numClients)
       return;
     this._log.debug("Client count: " + this.numClients + " -> " + numClients);
     this.numClients = numClients;
     if (numClients <= 1) {
       this._log.trace("Adjusting syncThreshold to SINGLE_USER_THRESHOLD");
       this.syncThreshold = SINGLE_USER_THRESHOLD;
     } else {
       this._log.trace("Adjusting syncThreshold to MULTI_DEVICE_THRESHOLD");
       this.syncThreshold = MULTI_DEVICE_THRESHOLD;
     }
     this.adjustSyncInterval();
   },
   /**
    * Check if we should be syncing and schedule the next sync, if it's not scheduled
    */
   checkSyncStatus: function checkSyncStatus() {
     // Should we be syncing now, if not, cancel any sync timers and return
     // if we're in backoff, we'll schedule the next sync.
     let ignore = [kSyncBackoffNotMet, kSyncMasterPasswordLocked];
     let skip = this.service._checkSync(ignore);
     this._log.trace("_checkSync returned \"" + skip + "\".");
     if (skip) {
       this.clearSyncTriggers();
       return;
     }
     // Only set the wait time to 0 if we need to sync right away
     let wait;
     if (this.globalScore > this.syncThreshold) {
       this._log.debug("Global Score threshold hit, triggering sync.");
       wait = 0;
     }
     this.scheduleNextSync(wait);
   },
   /**
    * Call sync() if Master Password is not locked.
    *
    * Otherwise, reschedule a sync for later.
    */
   syncIfMPUnlocked: function syncIfMPUnlocked() {
     // No point if we got kicked out by the master password dialog.
     if (Status.login == MASTER_PASSWORD_LOCKED &&
         Utils.mpLocked()) {
       this._log.debug("Not initiating sync: Login status is " + Status.login);
       // If we're not syncing now, we need to schedule the next one.
       this._log.trace("Scheduling a sync at MASTER_PASSWORD_LOCKED_RETRY_INTERVAL");
       this.scheduleAtInterval(MASTER_PASSWORD_LOCKED_RETRY_INTERVAL);
       return;
     }
     Utils.nextTick(this.service.sync, this.service);
   },
   /**
    * Set a timer for the next sync
    */
   scheduleNextSync: function scheduleNextSync(interval) {
     // If no interval was specified, use the current sync interval.
     if (interval == null) {
       interval = this.syncInterval;
     }
     // Ensure the interval is set to no less than the backoff.
     if (Status.backoffInterval && interval < Status.backoffInterval) {
       this._log.trace("Requested interval " + interval +
                       " ms is smaller than the backoff interval. " +
                       "Using backoff interval " +
                       Status.backoffInterval + " ms instead.");
       interval = Status.backoffInterval;
     }
     if (this.nextSync != 0) {
       // There's already a sync scheduled. Don't reschedule if there's already
       // a timer scheduled for sooner than requested.
       let currentInterval = this.nextSync - Date.now();
       this._log.trace("There's already a sync scheduled in " +
                       currentInterval + " ms.");
       if (currentInterval < interval && this.syncTimer) {
         this._log.trace("Ignoring scheduling request for next sync in " +
                         interval + " ms.");
         return;
       }
     }
     // Start the sync right away if we're already late.
     if (interval <= 0) {
       this._log.trace("Requested sync should happen right away.");
       this.syncIfMPUnlocked();
       return;
     }
     this._log.debug("Next sync in " + interval + " ms.");
     Utils.namedTimer(this.syncIfMPUnlocked, interval, this, "syncTimer");
     // Save the next sync time in-case sync is disabled (logout/offline/etc.)
     this.nextSync = Date.now() + interval;
   },
   /**
    * Incorporates the backoff/retry logic used in error handling and elective
    * non-syncing.
    */
   scheduleAtInterval: function scheduleAtInterval(minimumInterval) {
     let interval = Utils.calculateBackoff(this._syncErrors,
                                           MINIMUM_BACKOFF_INTERVAL,
                                           Status.backoffInterval);
     if (minimumInterval) {
       interval = Math.max(minimumInterval, interval);
     }
     this._log.debug("Starting client-initiated backoff. Next sync in " +
                     interval + " ms.");
     this.scheduleNextSync(interval);
   },
  /**
   * Automatically start syncing after the given delay (in seconds).
   *
   * Applications can define the `services.sync.autoconnectDelay` preference
   * to have this called automatically during start-up with the pref value as
   * the argument. Alternatively, they can call it themselves to control when
   * Sync should first start to sync.
   */
   delayedAutoConnect: function delayedAutoConnect(delay) {
     if (this.service._checkSetup() == STATUS_OK) {
       Utils.namedTimer(this.autoConnect, delay * 1000, this, "_autoTimer");
     }
   },
   autoConnect: function autoConnect() {
     if (this.service._checkSetup() == STATUS_OK && !this.service._checkSync()) {
       // Schedule a sync based on when a previous sync was scheduled.
       // scheduleNextSync() will do the right thing if that time lies in
       // the past.
       this.scheduleNextSync(this.nextSync - Date.now());
     }
     // Once autoConnect is called we no longer need _autoTimer.
     if (this._autoTimer) {
       this._autoTimer.clear();
     }
   },
   _syncErrors: 0,
   /**
    * Deal with sync errors appropriately
    */
   handleSyncError: function handleSyncError() {
     this._log.trace("In handleSyncError. Error count: " + this._syncErrors);
     this._syncErrors++;
     // Do nothing on the first couple of failures, if we're not in
     // backoff due to 5xx errors.
     if (!Status.enforceBackoff) {
       if (this._syncErrors < MAX_ERROR_COUNT_BEFORE_BACKOFF) {
         this.scheduleNextSync();
         return;
       }
       this._log.debug("Sync error count has exceeded " +
                       MAX_ERROR_COUNT_BEFORE_BACKOFF + "; enforcing backoff.");
       Status.enforceBackoff = true;
     }
     this.scheduleAtInterval();
   },
   /**
    * Remove any timers/observers that might trigger a sync
    */
   clearSyncTriggers: function clearSyncTriggers() {
     this._log.debug("Clearing sync triggers and the global score.");
     this.globalScore = this.nextSync = 0;
     // Clear out any scheduled syncs
     if (this.syncTimer)
       this.syncTimer.clear();
   },
 };
 const LOG_PREFIX_SUCCESS = "success-";
 const LOG_PREFIX_ERROR   = "error-";
 this.ErrorHandler = function ErrorHandler(service) {
   this.service = service;
   this.init();
 }
 ErrorHandler.prototype = {
   MINIMUM_ALERT_INTERVAL_MSEC: 604800000,   // One week.
   /**
    * Flag that turns on error reporting for all errors, incl. network errors.
    */
   dontIgnoreErrors: false,
   /**
    * Flag that indicates if we have already reported a prolonged failure.
    * Once set, we don't report it again, meaning this error is only reported
    * one per run.
    */
   didReportProlongedError: false,
   init: function init() {
     Svc.Obs.add("weave:engine:sync:applied", this);
     Svc.Obs.add("weave:engine:sync:error", this);
     Svc.Obs.add("weave:service:login:error", this);
     Svc.Obs.add("weave:service:sync:error", this);
     Svc.Obs.add("weave:service:sync:finish", this);
     this.initLogs();
   },
   initLogs: function initLogs() {
     this._log = Log.repository.getLogger("Sync.ErrorHandler");
     this._log.level = Log.Level[Svc.Prefs.get("log.logger.service.main")];
     this._cleaningUpFileLogs = false;
     let root = Log.repository.getLogger("Sync");
     root.level = Log.Level[Svc.Prefs.get("log.rootLogger")];
     let formatter = new Log.BasicFormatter();
     let capp = new Log.ConsoleAppender(formatter);
     capp.level = Log.Level[Svc.Prefs.get("log.appender.console")];
     root.addAppender(capp);
     let dapp = new Log.DumpAppender(formatter);
     dapp.level = Log.Level[Svc.Prefs.get("log.appender.dump")];
     root.addAppender(dapp);
     let fapp = this._logAppender = new Log.StorageStreamAppender(formatter);
     fapp.level = Log.Level[Svc.Prefs.get("log.appender.file.level")];
     root.addAppender(fapp);
     // Arrange for the FxA logs to also go to our file.
     Log.repository.getLogger("FirefoxAccounts").addAppender(fapp);
   },
   observe: function observe(subject, topic, data) {
     this._log.trace("Handling " + topic);
     switch(topic) {
       case "weave:engine:sync:applied":
         if (subject.newFailed) {
           // An engine isn't able to apply one or more incoming records.
           // We don't fail hard on this, but it usually indicates a bug,
           // so for now treat it as sync error (c.f. Service._syncEngine())
           Status.engines = [data, ENGINE_APPLY_FAIL];
           this._log.debug(data + " failed to apply some records.");
         }
         break;
       case "weave:engine:sync:error":
         let exception = subject;  // exception thrown by engine's sync() method
         let engine_name = data;   // engine name that threw the exception
         this.checkServerError(exception);
         Status.engines = [engine_name, exception.failureCode || ENGINE_UNKNOWN_FAIL];
         this._log.debug(engine_name + " failed: " + Utils.exceptionStr(exception));
         break;
       case "weave:service:login:error":
         this.resetFileLog(Svc.Prefs.get("log.appender.file.logOnError"),
                           LOG_PREFIX_ERROR);
         if (this.shouldReportError()) {
           this.notifyOnNextTick("weave:ui:login:error");
         } else {
           this.notifyOnNextTick("weave:ui:clear-error");
         }
         this.dontIgnoreErrors = false;
         break;
       case "weave:service:sync:error":
         if (Status.sync == CREDENTIALS_CHANGED) {
           this.service.logout();
         }
         this.resetFileLog(Svc.Prefs.get("log.appender.file.logOnError"),
                           LOG_PREFIX_ERROR);
         if (this.shouldReportError()) {
           this.notifyOnNextTick("weave:ui:sync:error");
         } else {
           this.notifyOnNextTick("weave:ui:sync:finish");
         }
         this.dontIgnoreErrors = false;
         break;
       case "weave:service:sync:finish":
         this._log.trace("Status.service is " + Status.service);
         // Check both of these status codes: in the event of a failure in one
         // engine, Status.service will be SYNC_FAILED_PARTIAL despite
         // Status.sync being SYNC_SUCCEEDED.
         // *facepalm*
         if (Status.sync    == SYNC_SUCCEEDED &&
             Status.service == STATUS_OK) {
           // Great. Let's clear our mid-sync 401 note.
           this._log.trace("Clearing lastSyncReassigned.");
           Svc.Prefs.reset("lastSyncReassigned");
         }
         if (Status.service == SYNC_FAILED_PARTIAL) {
           this._log.debug("Some engines did not sync correctly.");
           this.resetFileLog(Svc.Prefs.get("log.appender.file.logOnError"),
                             LOG_PREFIX_ERROR);
           if (this.shouldReportError()) {
             this.dontIgnoreErrors = false;
             this.notifyOnNextTick("weave:ui:sync:error");
             break;
           }
         } else {
           this.resetFileLog(Svc.Prefs.get("log.appender.file.logOnSuccess"),
                             LOG_PREFIX_SUCCESS);
         }
         this.dontIgnoreErrors = false;
         this.notifyOnNextTick("weave:ui:sync:finish");
         break;
     }
   },
   notifyOnNextTick: function notifyOnNextTick(topic) {
     Utils.nextTick(function() {
       this._log.trace("Notifying " + topic +
                       ". Status.login is " + Status.login +
                       ". Status.sync is " + Status.sync);
       Svc.Obs.notify(topic);
     }, this);
   },
   /**
    * Trigger a sync and don't muffle any errors, particularly network errors.
    */
   syncAndReportErrors: function syncAndReportErrors() {
     this._log.debug("Beginning user-triggered sync.");
     this.dontIgnoreErrors = true;
     Utils.nextTick(this.service.sync, this.service);
   },
   /**
    * Finds all logs older than maxErrorAge and deletes them without tying up I/O.
    */
   cleanupLogs: function cleanupLogs() {
     let direntries = FileUtils.getDir("ProfD", ["weave", "logs"]).directoryEntries;
     let oldLogs = [];
     let index = 0;
     let threshold = Date.now() - 1000 * Svc.Prefs.get("log.appender.file.maxErrorAge");
     this._log.debug("Log cleanup threshold time: " + threshold);
     while (direntries.hasMoreElements()) {
       let logFile = direntries.getNext().QueryInterface(Ci.nsIFile);
       if (logFile.lastModifiedTime < threshold) {
         this._log.trace(" > Noting " + logFile.leafName +
                         " for cleanup (" + logFile.lastModifiedTime + ")");
         oldLogs.push(logFile);
       }
     }
     // Deletes a file from oldLogs each tick until there are none left.
     let errorHandler = this;
     function deleteFile() {
       if (index >= oldLogs.length) {
         errorHandler._log.debug("Done deleting files.");
         errorHandler._cleaningUpFileLogs = false;
         Svc.Obs.notify("weave:service:cleanup-logs");
         return;
       }
       try {
         let file = oldLogs[index];
         file.remove(false);
         errorHandler._log.trace("Deleted " + file.leafName + ".");
       } catch (ex) {
         errorHandler._log._debug("Encountered error trying to clean up old log file '"
                                  + oldLogs[index].leafName + "':"
                                  + Utils.exceptionStr(ex));
       }
       index++;
       Utils.nextTick(deleteFile);
     }
     if (oldLogs.length > 0) {
       this._cleaningUpFileLogs = true;
       Utils.nextTick(deleteFile);
     } else {
       this._log.debug("No logs to clean up.");
     }
   },
   /**
    * Generate a log file for the sync that just completed
    * and refresh the input & output streams.
    *
    * @param flushToFile
    *        the log file to be flushed/reset
    *
    * @param filenamePrefix
    *        a value of either LOG_PREFIX_SUCCESS or LOG_PREFIX_ERROR
    *        to be used as the log filename prefix
    */
   resetFileLog: function resetFileLog(flushToFile, filenamePrefix) {
     let inStream = this._logAppender.getInputStream();
     this._logAppender.reset();
     if (flushToFile && inStream) {
       this._log.debug("Flushing file log.");
       try {
         let filename = filenamePrefix + Date.now() + ".txt";
         let file = FileUtils.getFile("ProfD", ["weave", "logs", filename]);
         let outStream = FileUtils.openFileOutputStream(file);
         this._log.trace("Beginning stream copy to " + file.leafName + ": " +
                         Date.now());
         NetUtil.asyncCopy(inStream, outStream, function onCopyComplete() {
           this._log.trace("onCopyComplete: " + Date.now());
           this._log.trace("Output file timestamp: " + file.lastModifiedTime);
           Svc.Obs.notify("weave:service:reset-file-log");
           this._log.trace("Notified: " + Date.now());
           if (filenamePrefix == LOG_PREFIX_ERROR &&
               !this._cleaningUpFileLogs) {
             this._log.trace("Scheduling cleanup.");
             Utils.nextTick(this.cleanupLogs, this);
           }
         }.bind(this));
       } catch (ex) {
         Svc.Obs.notify("weave:service:reset-file-log");
       }
     } else {
       Svc.Obs.notify("weave:service:reset-file-log");
     }
   },
   /**
    * Translates server error codes to meaningful strings.
    *
    * @param code
    *        server error code as an integer
    */
   errorStr: function errorStr(code) {
     switch (code.toString()) {
     case "1":
       return "illegal-method";
     case "2":
       return "invalid-captcha";
     case "3":
       return "invalid-username";
     case "4":
       return "cannot-overwrite-resource";
     case "5":
       return "userid-mismatch";
     case "6":
       return "json-parse-failure";
     case "7":
       return "invalid-password";
     case "8":
       return "invalid-record";
     case "9":
       return "weak-password";
     default:
       return "generic-server-error";
     }
   },
   shouldReportError: function shouldReportError() {
     if (Status.login == MASTER_PASSWORD_LOCKED) {
       this._log.trace("shouldReportError: false (master password locked).");
       return false;
     }
     if (this.dontIgnoreErrors) {
       return true;
     }
     let lastSync = Svc.Prefs.get("lastSync");
     if (lastSync && ((Date.now() - Date.parse(lastSync)) >
         Svc.Prefs.get("errorhandler.networkFailureReportTimeout") * 1000)) {
       Status.sync = PROLONGED_SYNC_FAILURE;
       if (this.didReportProlongedError) {
         this._log.trace("shouldReportError: false (prolonged sync failure, but" +
                         " we've already reported it).");
         return false;
       }
       this._log.trace("shouldReportError: true (first prolonged sync failure).");
       this.didReportProlongedError = true;
       return true;
     }
     // We got a 401 mid-sync. Wait for the next sync before actually handling
     // an error. This assumes that we'll get a 401 again on a login fetch in
     // order to report the error.
     if (!this.service.clusterURL) {
       this._log.trace("shouldReportError: false (no cluster URL; " +
                       "possible node reassignment).");
       return false;
     }
     return ([Status.login, Status.sync].indexOf(SERVER_MAINTENANCE) == -1 &&
             [Status.login, Status.sync].indexOf(LOGIN_FAILED_NETWORK_ERROR) == -1);
   },
   get currentAlertMode() {
     return Svc.Prefs.get("errorhandler.alert.mode");
   },
   set currentAlertMode(str) {
     return Svc.Prefs.set("errorhandler.alert.mode", str);
   },
   get earliestNextAlert() {
     return Svc.Prefs.get("errorhandler.alert.earliestNext", 0) * 1000;
   },
   set earliestNextAlert(msec) {
     return Svc.Prefs.set("errorhandler.alert.earliestNext", msec / 1000);
   },
   clearServerAlerts: function () {
     // If we have any outstanding alerts, apparently they're no longer relevant.
     Svc.Prefs.resetBranch("errorhandler.alert");
   },
   /**
    * X-Weave-Alert headers can include a JSON object:
    *
    *   {
    *    "code":    // One of "hard-eol", "soft-eol".
    *    "url":     // For "Learn more" link.
    *    "message": // Logged in Sync logs.
    *   }
    */
   handleServerAlert: function (xwa) {
     if (!xwa.code) {
       this._log.warn("Got structured X-Weave-Alert, but no alert code.");
       return;
     }
     switch (xwa.code) {
       // Gently and occasionally notify the user that this service will be
       // shutting down.
       case "soft-eol":
         // Fall through.
       // Tell the user that this service has shut down, and drop our syncing
       // frequency dramatically.
       case "hard-eol":
         // Note that both of these alerts should be subservient to future "sign
         // in with your Firefox Account" storage alerts.
         if ((this.currentAlertMode != xwa.code) ||
             (this.earliestNextAlert < Date.now())) {
           Utils.nextTick(function() {
             Svc.Obs.notify("weave:eol", xwa);
           }, this);
           this._log.error("X-Weave-Alert: " + xwa.code + ": " + xwa.message);
           this.earliestNextAlert = Date.now() + this.MINIMUM_ALERT_INTERVAL_MSEC;
           this.currentAlertMode = xwa.code;
         }
         break;
       default:
         this._log.debug("Got unexpected X-Weave-Alert code: " + xwa.code);
     }
   },
   /**
    * Handle HTTP response results or exceptions and set the appropriate
    * Status.* bits.
    *
    * This method also looks for "side-channel" warnings.
    */
   checkServerError: function (resp) {
     switch (resp.status) {
       case 200:
       case 404:
       case 513:
         let xwa = resp.headers['x-weave-alert'];
         // Only process machine-readable alerts.
         if (!xwa || !xwa.startsWith("{")) {
           this.clearServerAlerts();
           return;
         }
         try {
           xwa = JSON.parse(xwa);
         } catch (ex) {
           this._log.warn("Malformed X-Weave-Alert from server: " + xwa);
           return;
         }
         this.handleServerAlert(xwa);
         break;
       case 400:
         if (resp == RESPONSE_OVER_QUOTA) {
           Status.sync = OVER_QUOTA;
         }
         break;
       case 401:
         this.service.logout();
         this._log.info("Got 401 response; resetting clusterURL.");
         Svc.Prefs.reset("clusterURL");
         let delay = 0;
         if (Svc.Prefs.get("lastSyncReassigned")) {
           // We got a 401 in the middle of the previous sync, and we just got
           // another. Login must have succeeded in order for us to get here, so
           // the password should be correct.
           // This is likely to be an intermittent server issue, so back off and
           // give it time to recover.
           this._log.warn("Last sync also failed for 401. Delaying next sync.");
           delay = MINIMUM_BACKOFF_INTERVAL;
         } else {
           this._log.debug("New mid-sync 401 failure. Making a note.");
           Svc.Prefs.set("lastSyncReassigned", true);
         }
         this._log.info("Attempting to schedule another sync.");
         this.service.scheduler.scheduleNextSync(delay);
         break;
       case 500:
       case 502:
       case 503:
       case 504:
         Status.enforceBackoff = true;
         if (resp.status == 503 && resp.headers["retry-after"]) {
           let retryAfter = resp.headers["retry-after"];
           this._log.debug("Got Retry-After: " + retryAfter);
           if (this.service.isLoggedIn) {
             Status.sync = SERVER_MAINTENANCE;
           } else {
             Status.login = SERVER_MAINTENANCE;
           }
           Svc.Obs.notify("weave:service:backoff:interval",
                          parseInt(retryAfter, 10));
         }
         break;
     }
     switch (resp.result) {
       case Cr.NS_ERROR_UNKNOWN_HOST:
       case Cr.NS_ERROR_CONNECTION_REFUSED:
       case Cr.NS_ERROR_NET_TIMEOUT:
       case Cr.NS_ERROR_NET_RESET:
       case Cr.NS_ERROR_NET_INTERRUPT:
       case Cr.NS_ERROR_PROXY_CONNECTION_REFUSED:
         // The constant says it's about login, but in fact it just
         // indicates general network error.
         if (this.service.isLoggedIn) {
           Status.sync = LOGIN_FAILED_NETWORK_ERROR;
         } else {
           Status.login = LOGIN_FAILED_NETWORK_ERROR;
         }
         break;
     }
   },
 };